The invention relates to a catheter having inflatable means for dilation of the prostate urethra, and to a method for the treatment of benign prostatic hyperplasia.
Balloon catheters are widely used for dilation of undesirable tissue in body vessels. For instance, U.S. Pat. No. 4,636,195 discloses removal of constrictions caused by deposition of plaque in arteries by a balloon catheter. The disclosed catheter has two smaller ring balloons spaced around a central dilation balloon. The smaller ring balloons provide a chamber around a body of plaque, and help to hold the catheter body in place. Other multiple balloon catheters are disclosed in U.S. Pat. Nos. 4,573,966 and 4,610,662. The two balloons of these catheters are placed in a vascular passageway to seal off a constricted area, and dissolving fluid is supplied to the enclosed area to dissolve the constrictive tissue.
Treatment of obstructive tissue in the prostate urethra with a balloon catheter is disclosed in U.S. Pat. No. 4,660,560 which describes a catheter having a Foley balloon for anchoring the catheter by inflation within the bladder, and an annular balloon for dilation of the prostate urethra. Proper location of the annular balloon is attained by introducing a cystoscope into the prostate urethra. The operation of the cystoscope to determine the location of the prostate urethra with respect to the bladder neck is cumbersome, and is avoided by the invention as described below.
In Application Ser. No. 192,432 there is described and claimed an apparatus for dilation of the prostate urethra, which apparatus comprises an impervious urinary catheter for insertion in the prostate urethra, said catheter having a proximal section and a distal section: dilation means mounted on said proximal section of the catheter; location means mounted on the catheter at a distance from the dilation means such that the location means is positioned at the bulbous urethra distal from the external sphincter to hold the catheter in place when the dilation means is positioned at the prostate urethra; and activating means located at said distal section of the catheter for activating said dilation means and said location means.
As used herein, the term impervious means both that the material from which the catheter is made is impervious and also that the catheter tube is impervious in that the tubular wall does not have any openings along its length.
In a preferred embodiment of the above invention, the dilation means is a dilation balloon and the location means is a location balloon.
The dilation balloon is preferably made of a limited distensible material such that the balloon can not expand from its initial deflation diameter to substantially beyond a predetermined diameter regardless of the internal pressure applied to the balloon.
Application Ser. No. 192,432 also describes and claims a method for the treatment of benign prostatic hyperplasia which comprises inserting into a prostate urethra an impervious urinary catheter having dilation means for dilating the prostate urethra and location means for location of the dilation means at the prostate urethra, locating and fixing said location means, placing and dilating said dilation means and thereby dilating the prostate urethra with said dilation means to alleviate obstruction of the prostate urethra resulting from benign prostatic hyperplasia, deactivating said dilation means and location means, and removing said catheter from said prostate urethra.
In said method the dilation means is preferably a dilation balloon and the location means is preferably a location balloon.
To facilitate performance of the method the location balloon is axially mounted on said catheter at a distance from said dilation balloon such that the location balloon is positioned at the bulbous urethra distal from the external sphincter to hold the catheter in place when the dilation balloon is positioned at the prostate urethra, and said location balloon on inflation is sized to fit in the bulbous urethra.
A convenient way to properly place the catheter is by rectal palpation wherein the doctor feels the bulbous urethra by rectal palpation and locates the location balloon therein as hereinafter described.
It has now been found that palpation is facilitated when the distal end of the dilation balloon is provided with an integral protuberance which makes it slightly stiffer and thicker than the remainder of the balloon whereby palpation is enhanced when the protuberance is placed at the apex of the prostate. This structure facilitates correct placement of the dilation balloon in the prostate urethra and the location balloon in the bulbous urethra.